Exemplary aspects of the present invention relate to an optical device and a projector.
Related art, projectors are disposed with an optical device including: plural optical parts disposed on an optical path of light beams emitted from a light source; and an optical parts-use casing where an illumination optical axis of the light beams is set inside and which houses the plural optical parts and is disposed at a predetermined position.
Here, as the optical parts, plural optical elements that change the optical characteristics of the light beams emitted from the light source, and plural mirrors that reflect and/or transmit the light beams emitted from the light source and guide the light beams on a predetermined illumination optical axis, are used.
In such a projector, it is necessary to relatively position the optical elements serving as the optical parts and to prevent displacement of the inclination positions of the reflective surfaces of the mirrors in order to obtain a sharper projection image. Additionally, a retention structure that can adjust the orientations of the mirrors has been disclosed in JP-A-2000-321661.
In the mirror retention structure described in JP-A-2000-321661, center portions at lower ends of the mirrors are nipped by one protruding portion formed on the optical parts-use casing and a substantially U-shaped plate spring attached with a fixing screw to the optical parts-use casing. Also, two places at upper ends of the mirrors are nipped by two eccentric discs pivotably attached to the optical parts-use casing and a substantially U-shaped plate spring attached with a fixing screw to the optical parts-use casing. Additionally, by independently pivoting each eccentric disc using a tool, such as a driver, at least one of the inclination of the vertical direction of the mirrors and the inclination of the horizontal direction of the mirrors is adjustable.